Pre Seed Burnoff: If the daytime temperature is forecasted to reach a minimum 8-10°C, plan to spray once the temperature reaches a minimum 5°C. It is best to spray in the morning or afternoon as temperatures rise throughout the day. Avoid application into the evening if the temperature is to drop below 10°C. In this case, stop spraying 1.5 to 2 hours before sunset or before it drops below 10°C. This allows time for the product to move from the leaves to the growing points of the plants.

In Crop: Try to avoid the heat of the day as plants will grow less actively in extreme heat; Monsanto Canada does not recommend spraying in temperatures above 30°C. Spraying later in the day or into the evening is fine as well, but spraying in the morning allows the plants to ‘recharge’ overnight – be careful of excessive dew on the plants as this may cause the herbicide to run off the plants resulting in reduced control.

Pre Harvest: Evening and early morning temperatures of 0 to -4°C should not impact the performance of Roundup agricultural herbicides for pre harvest as cool seasonal temperatures have conditioned perennial weeds. However, do not start applying until late morning or afternoon and only apply if forecasted temperatures are to remain higher than 8-10°C for a minimum of 2 hours.

Post Harvest: If forecasted daytime temperatures are a minimum of 8-10°C, start spraying in the morning provided there has not been a killing frost and the dew or snowmelt is not causing the herbicide to run off the plant. The weeds need at least 2-4 hours of temperatures above 8-10°C to translocate the Roundup brand agricultural herbicide. With cool temperatures, stop spraying 2 hours before sunset.

Physiological maturity is the key for timing a pre-harvest glyphosate application. Physiological maturity is reached once seed moisture content is less than 30%. The table below provides visual indicators of physiological maturity.

Roundup Transorb® HC or Roundup WeatherMAX® herbicides should be applied at 0.67 L/ac for pre-harvest applications. Using 10 gallons of water per acre is recommended for dense crop canopies and for weeds that are hidden by the crop, such as dandelions. However, registered water volumes range from 5 to 10 gallons per acre. Crop canopy penetration is critical for successful weed control.

For detailed information on a pre-harvest application click here to download our digital Pre-Harvest Staging guide. Or call 1-800-667-4944 to request a copy.

Proper translocation prior to animal re-entry is imperative to effective weed control. To ensure proper weed control and forage removal, Monsanto recommends grazing not resume for 3 to 5 days after spraying.

Grazing is safe for the animals as soon as the herbicide has dried. However, proper translocation must occur before grazing is allowed to ensure proper weed control.

When a Re-entry Interval is not listed on a chemical label, it is recommended to wait until the chemical has dried, however, assume annual weeds require a minimum of 24 hours of good weather conditions for proper translocation.

For perennial weed and forage control, wait a minimum of 72 hours for proper translocation of the chemical through the target plants before allowing grazing.

Can I mix Roundup brand agricultural herbicides together?
Mixing Roundup brand agricultural products together (for example Roundup Transorb® HC and Roundup WeatherMAX®) is fine, however, because of formulation differences, be aware that the rainfast period will only be guaranteed to that of the longer rainfast guarantee (which in this example is Roundup Transorb HC – 60 minutes).

Can I mix Roundup brand agricultural herbicides with other glyphosates?
Monsanto Canada will not guarantee performance of Roundup brand agricultural herbicides when tank mixed with other glyphosates.

Can I add a Roundup agricultural herbicide to Rustler® liquid herbicide to top it up?
Generally, there should not be any problem tank-mixing Roundup brand agricultural herbicides and Rustler when mixed in a diluted system. *Do not mix products straight without water, as this could cause issues. As long as the mix is occurring with sufficient water there should not be a problem.

Can I tank mix insecticides with Roundup® brand agricultural herbicides?
Currently there are NO insecticide tank mixes registered on the Roundup brand agricultural herbicide labels.

Good, clean water is very important to maximizing the performance of Roundup herbicide. Water free from dirt and soil particles is essential, as glyphosate readily binds to these particles. Glyphosate also binds easily (and tightly) to positively charged ions (cations) such as calcium (Ca), magnesium (Mg), Iron (Fe), and sometimes manganese (Mn) or zinc (Zn). When water contains a high level of these cations, it is refered to as hard water. Water hardness is usually measured in parts per million (ppm). Depending on the water volume being used, water can be unsuitable for use with Roundup herbicides at different levels of hardness. As a rule of thumb, any water that tests over 700 ppm should not be used with glyphosate, regardless of water volume. The following chart should be used as a guideline:

If the water hardness is above the recommended limits for intended use rate and water volume, the following measures can be taken to minimize the impact of hard water. The following recommendations are NOT a guarantee of overcoming the problem.

Roundup herbicide rate

Water volume

Hardness limit

Comments

0.33L/ac – 0.67L/ac

5 GPA

700 ppm

Do not use water volumes higher than 10 GPA when Roundup use rates are less than 0.33 L/ac

10 GPA

350 ppm

> 10 GPA

Not recommended

> 0.67L/ac

5 GPA

700 ppm

Because of possible precipitate problems, 700 ppm is still the threshold at 0.67L/ac with 5 GPA

10 GPA

700 ppm

> 10 GPA

350 ppm

Find another water source with softer water

Lower the water volume to decrease the amount of glyphosate tie-up – stay within acceptable water volume range as per the product label

Add ammonium sulphate (AMS). AMS comes in a dry (21-0-0-24) or liquid (8-0-0-9) form. Dry AMS should be added at a rate of 2% w/w (2kg for every 100L of water); liquid AMS should be added at a rate of 1% v/v (1L for every 100L of water).

Increase rate of Roundup by 10-15% to offset any tie-up – stay within labeled limits

Glyphosate binds very tightly to soil particles, including small dust particles. Dust on the leaves can deactivate Roundup once it contacts the leaf surface.

How do I determine if there is too much dust on the leaves?
A quick way to determine if there is too much dust on the leaves is to wipe your thumb across part of the leaf. If you can see a definite mark where you have wiped, there is too much dust on the leaves, and you may not see optimal performance.

How do I overcome dust on the leaves?

Increase the rate of herbicide by approximately 25% (Ensure you are still within labeled rates)

Genuity® Roundup Ready® Canola:
2 applications of 0.33 L/ac applied at the 0-6 leaf stage. (*Monsanto Canada recommends a minimum of 10 days between 1st and 2nd in-crop application.) Often the first in-crop treatment is applied at the 1-3 leaf stage; with a second treatment at the 4-6 leaf stage.
OR
1 application of 0.5 L/ac anytime from emergence to the 6 leaf stage.

Annual Weeds: When applying Roundup WeatherMAX® under good growing conditions, seeding may start 4-6 hours later! For all other Roundup brand agricultural herbicides (or under stressful weather conditions), you must wait a minimum of 24 hours before seeding or working the land.

Perennial Weeds: With all Roundup brand agricultural herbicides we recommend that you wait 72 hours under good growing conditions before seeding or tillage. If it’s cool and cloudy wait an extra day before tillage so the herbicide has sufficient time to translocate to the roots of the weed.

Roundup® brand agricultural herbicides do not require heated storage. Roundup® brand agricultural herbicides may be stored at cold temperatures; the product will not freeze, however it may thicken slightly. Agitate well prior to use (transportation to field is often enough agitation).

The effect of frost on weeds depends on the length and harshness of the frost. In general terms, dandelions are the most tolerant to frost, while perennial sow-thistle and Canada thistle are the most sensitive. If in doubt, it is best to wait a day or two after the frost and assess the damage to the weeds – if they are still 60% green, they should still be susceptible to Roundup brand agricultural herbicides.

When spraying annual weeds, mix a 0.67 percent solution of the product in water. For harder to control perennial weeds, mix a 1.34 percent solution of the product in water. These recommendations can be found in the “Application Equipment” section of the product label.

Two
things to be concerned about with a frost on your Genuity® Roundup Ready® crops –
weed control and crop tolerance. The weeds will be affected by a frost much the
same way they would be if it were a pre-seed application. Similarly, the crop
must also have time to recover from the frost to minimize crop injury.

0 to
-4°C: Wait at least 24 hours to assess damage to the weeds and the crop.
Spraying can resume if forecasted temperatures are to remain higher than 8°C
for a minimum of 2 hours after the application.≤ -5°C:
Wait at least 2 days to assess damage to crop and weeds. Spraying can resume if
forecasted temperatures are to remain higher than 8°C for a minimum of 2 hours
after the application.

Weeds
must be >60% green and actively growing for good results and Crop
needs to show signs of regrowth before spraying can take place.

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